From 9c5a170677c3c8facc83e931a57f4c99c0511ae0 Mon Sep 17 00:00:00 2001
From: "Russell King (Oracle)" <rmk+kernel@armlinux.org.uk>
Date: Thu, 27 Oct 2022 14:10:37 +0100
Subject: [PATCH] net: phylink: add phylink_get_link_timer_ns() helper

Add a helper to convert the PHY interface mode to the required link
timer setting as stated by the appropriate standard. Inappropriate
interface modes return an error.

Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---
 include/linux/phylink.h | 24 ++++++++++++++++++++++++
 1 file changed, 24 insertions(+)

--- a/include/linux/phylink.h
+++ b/include/linux/phylink.h
@@ -614,6 +614,30 @@ int phylink_speed_up(struct phylink *pl)
 
 void phylink_set_port_modes(unsigned long *bits);
 
+/**
+ * phylink_get_link_timer_ns - return the PCS link timer value
+ * @interface: link &typedef phy_interface_t mode
+ *
+ * Return the PCS link timer setting in nanoseconds for the PHY @interface
+ * mode, or -EINVAL if not appropriate.
+ */
+static inline int phylink_get_link_timer_ns(phy_interface_t interface)
+{
+	switch (interface) {
+	case PHY_INTERFACE_MODE_SGMII:
+	case PHY_INTERFACE_MODE_QSGMII:
+	case PHY_INTERFACE_MODE_USXGMII:
+		return 1600000;
+
+	case PHY_INTERFACE_MODE_1000BASEX:
+	case PHY_INTERFACE_MODE_2500BASEX:
+		return 10000000;
+
+	default:
+		return -EINVAL;
+	}
+}
+
 void phylink_mii_c22_pcs_decode_state(struct phylink_link_state *state,
 				      u16 bmsr, u16 lpa);
 void phylink_mii_c22_pcs_get_state(struct mdio_device *pcs,
